1. Field of the Invention
This invention relates generally to piers for supporting a mobile home coach and more specifically to an improved pier head that maintains some support to the coach even as the distance between the coach and the ground changes.
2. Description of the Related Art
The drawing labeled FIG. 1 PRIOR ART shows a portion of a typical conventional support structure for a mobile home coach. A plurality of rails or support beams, such as beam 10, are attached to the underside of the coach to provide a level platform for supporting the coach body. Beam 10 is typically an I-beam, as shown, but may be a C-beam or other configuration having a large bottom flange 12 that carries the moment forces.
A coach sixty feet long and twelve feet wide typically has two parallel spaced-apart sixty foot beams 10 running the length of the coach. A furnished sixty foot by twenty foot coach weighs in the range of 22,000 pounds. Beam 10, or the like, is supported off the ground by jack stands or piers, denoted generally as 20. Each pier 20 includes a stand, denoted generally as 21, for placement on the ground and a head, denoted genes-ally as 30P, for placement under a load to be supported. Stand 21 includes height adjustment means, denoted generally as 22, such as threaded rod 23 and adjustment nut 24. Head 30P includes a support plate 50P for placement under I-beam flange 12 for supporting beam 10. Piers 20 are placed typically at five foot intervals such that, for the above example, twenty-two piers would be used and each pier 20 should support about one thousand pounds. Adjustment nut 24 adjusts the height of support plate 50P above the ground and is used to adjust the height of each pier such that beam 10 is uniformly supported in a level position. Since the height of each pier 20 affects the load of the other piers 20, it is difficult to uniformly align all of the platforms 22 supporting beam 10 such that beam 10 is level. The difference between a given pier supporting one thousand pounds or zero pounds may be a partial turn of the adjusting nut 24 of that pier or an adjacent pier.
A major problem with the above-described conventional practice is that the levelness of beam 10 at a given location may not be an accurate indication that the beam is being supported at that location. Additionally, with passage of time, because of ground settling and other factors, some piers 20 carry no load and some carry a very large load. It is not uncommon to be able to simply pull out by hand one-third to one-one half of piers 20 because they are carrying no load. This condition is undesirable for several reasons. The large stresses in the few load carrying piers 20 may result in failure during an earthquake or the like. The coach frame will tend to bend in the unsupported areas such that the coach body is distorted and interior floors are bowed.
Therefore, it is desirable to have an improved pier that will maintain a desired load even after increased separation between ground and coach.
It is also desirable that with such an improved pier, any increased separation between ground and coach is easily observable, thus indicating that corrective action should be taken.